Mozilla announced the release of Firefox version 133, along with extended support versions 115.18.0 and 128.5.0. The new version fixes 18 vulnerabilities , three of which are classified as critical. These include memory flaws that could allow malicious code to execute when interacting with web pages specifically designed to exploit these weaknesses.
This new version of Firefox 133 highlights the addition of Bounce Tracking Protection, an improvement to the strict tracking protection mode (ETP, Enhanced Tracking Protection).
This new mechanism focuses on preventing tracking through redirects by detecting specific tracking patterns and periodically deleting cookies and local data used for tracking purposes. Unlike previous methods, which relied on lists of known trackers, this protection uses advanced heuristics to identify and neutralize new forms of tracking by analyzing behavior after redirects.
Tracking through redirects works by temporarily redirecting users to tracker sites before taking them to their final destination. During this process, trackers store cookies and other data in local storage. This allows them to circumvent cross-site restrictions implemented by browsers, as the cookies are set outside the context of the original site. Firefox's new protection automatically removes this data, mitigating these invasive tactics.
Another improvement in Firefox 133 is the new functionality in the open tabs menu , accessible from the button in the upper right corner . Now, users can see a list of open tabs on other devices linked to the same Mozilla account in the sidebar , making it easier to access and synchronize them across multiple devices.
Regarding cookie handling, Firefox adjusts the "expire" attribute considering the difference between the server time and the local time. If the system has a future time lag, cookies remain valid according to the server time, thus improving accuracy in environments with inconsistent time settings.
The Windows edition now includes GPU acceleration for the Canvas2D API , and the Fetch API now includes support for the "keepalive" parameter, allowing HTTP requests to remain active even after closing a page, ideal for sending data at the end of sessions.
In the Android version, desktop mode is enabled by default on devices with large screens , and now content copied in private browsing mode is marked as confidential, displaying warnings to the user.
For developers, Firefox 133 introduces new capabilities in dialog handling through the "beforetoggle" and "toggle" events on elements. , which now allow you to capture states before opening or closing dialog boxes.
Other notable changes include :
- PiP “picture in picture” has received improvements and is supported on more sites.
- Added support for the contenteditable attribute set to plain text mode, and the :has-slotted CSS pseudo-class. Both can be enabled in the about:config advanced settings.
- The browser extends its support for Web Workers, allowing the use of API permissions through the WorkerNavigator.permissions property.
- Multimedia elements and added the onwaitingforkey event, designed to handle situations where playback stops due to lack of decryption keys.
If you're interested in learning more, you can check out the release notes at the following link.
How to install Firefox on Linux?
If you're already a Firefox user, you should know that you can easily update to the latest version by accessing the settings menu. Those with automatic updates enabled don't need to worry, as they will receive the new version without any manual intervention.
Alternatively, if you prefer not to wait for the automatic update, you can do it manually by going to Menu > Help > About Firefox. This will open a window showing the installed version and, if the feature is enabled, it will check for available updates.
For users of Ubuntu, Linux Mint, and other Ubuntu derivatives, it's also possible to update Firefox via the official PPA . To do so, open a terminal and enter the following commands:
sudo add-apt-repository ppa:ubuntu-mozilla-security/ppa -y sudo apt-get update sudo apt install firefox
Another available installation option is via Flatpak. To use this method, you need to have Flatpak support on your system. Once enabled, you can install Firefox by running the following command in the terminal:
flatpak install flathub org.mozilla.firefox
As for those who already have the browser installed, it is enough to execute the following command to not only update Firefox, but also all its applications that are in Flatpak format:
flatpack update
In the case of those who prefer the use of Snap, the installation of the browser can be done by typing the following command:
sudo snap install firefox
And to update the applications that we have installed in Snap format, just type the following in the terminal:
sudo snap refresh